Internal combustion engine



. Nov.l9,1940.

E. s. HALL i 2,222,294

INTERNAL COMBUSTION ENGINE Filed Feb. 8, 1958 2 S heet's-Shee t 1INVENTOR.

ATTORNEYS.

Nov. 19, 1940.

I E. SJFIIALL 2,222,294

INTERNAL COMBUSTION ENGINE 2 Filed Feb. 8, 1938 2 Sheets-Sheet 2 Fiq-iM- IN V EN TOR.

ATTORNEYS.

Patented Nov. 19, 1940 UNITED STATES INTERNAL COMBUSTION ENGINE Edwin S.Hall, New Haven, Conn. Application February 8, 1938, Serial No. 189,401

2 Claims.

engines of the type having cylinders parallel to the shaft, commonlycalled barrel type? or round engines, and is particularly concerned withthe normal type of round engine, (1. e. that type having double-endedpiston members serving two similar roups of. working cylinders with thereciprocating-rotary mechanism between them), tho some of the featuresof the invention are applicable to other types of engines, aswill beevident. This application is a continuation in part of my copendingapplication Serial Number 67,017 filed March 4, 1936.

An object of this invention is to provide an 35 efiicient and compactengine capable of delivering an unusually large'amount of power for itsbulk with extremely smooth operation. To this end, the inventionconsists of a normal round engine with preferably an odd number of 2Gdouble-ended piston members serving two groups of working cylinders,operating on the two-stroke cycle, with air for combustion furnished byseparate blower means.

In two-stroke engines, the piston may over- 35 run both intake andexhaust ports at the same time, but uniflow scavenge is preferable with4 intake at one end of the cylinder and exhaust at the other. In normalround engines, uniflow scavenge can be obtained by usingpiston-controlled ports for intake and valves for exhaust, or viceversa. An object of this invention is to provide a normal barrel engineoperable on the two-stroke cycle with uniflow'scavenge, with both portsin the cylinder walls and a valve 5 system. Preferably the intake may bethru piston-controlled ports, the valve system handling exhaust. but thedirection of scavenge might be reversed if desired, with the valvesystem handling intake and the pistons uncovering exhaust ports.

Relative to the valve system, an object of the invention is to provide avery simple system comprising two disc valves, each serving an entiregroup of cylinders, and mounted on eccentrics on the shaft so as tocontribute to the dynamic balance of the engine, and so driven that thespeed of the valve relative to the port sealing means is relatively slowduring high pressure portions of the cycle, but*very much faster duringopening and closing of the ports, to provide rapid opening and closingof the ports and to permit very large port openings for free flow of thegases. Further objects are to provde improved driving, sealing, cooling,and oil control means for disc valves.

. (31. 123-58) This invention relates to Internal combustion Goodscavenge and favorable combustion conditions can be obtained with theintake ports long enough radially to have a nozzle effect andtangentially inclined to give an orderly swirl to the scavenge air as itenters the cylinders. It 5 is also desirable to be able to machine allports. Objects of this invention are to provide these conditions byusing individual cylinders each with a ring of tangentially inclinedintake pOlbS opening into the cylinder, and to provide uniformdistribution of the scavenge air by serving all the ports of the severalcylinders of each group from a common windchest thru which the cylindersextend.

The two windchests must be supplied with air at pressure somewhatgreater than atmospheric, from the blower system. Positive displacementblowers could be used, but centrifugal blowers have less bulk for theamount of air delivered, and are therefore preferred. The most seriousproblem involved in the use of centrifugal ablowers is to provide asufiiciently sturdy drive, and it is an object of this invention toprovide an improved method of driving and mounting centrifugal blowers.To deliver enough air at the required pressure to scavenge a 1000 H. P.enine may require more than 200 H. P., and the step-up gearing mustdeliver that power continuously with the blower speed ten times enginespeed or more. Gear tooth loads are very severe and impeller inertiaforces are terrific; the gearing must be protected from shock resultingfrom irregular operation of the engine shaft. An object of thisinvention is to reduce the gear tooth loading to a fraction of what itwould be ordinarily by providing a system of multiple blowers, insteadof the usual single blower. Further objects are to provide a simple andsymmetrical system of gearing in which each gear can be maintained inalignment by being mounted on a pair of adequate bearings, cantileverloading being avoided; and to provide cushion and clutch means to avoidshock on the ears; and to provide means for assembling and mounting eachblower in a manner insuring c0!'- s5 rect meshing of its drive pinion.

In round engines of both the normal and opposed-piston types, thedriving and disposition of such accessories as oil and water pumps, generator, tachometer. etc., have been something of a problem. An object ofthis invention is to provide 'a workmanlike system of driving theaccessories of a barrel engine in a manner permitting their convenientand accessible location. Within each group of cylinders, a plurality of[iii bevel gears are mounted on their own bearings and driven by asingle gear on the engine shaft,

and radial'dri've shafts each associated with its accessory or group ofaccessories are inserted 5 between the cylinders to connect with thebevel gears, the accessory or group thereof being mounted on a flange onthe outside of the engine in a convenient and accessible position.

In any two-stroke engine, it is desirable to use fuel injection to avoidloss of unused fuel thru the exhaust. An object of this invention is toprovide a fuel injection system for a barrelengine with radiallyarranged pump units driven from a cam on the engine shaft, each pumpunit being associated with its own nozzle, both pump and injectionnozzle being easily accessible. Long high-pressure pipes areavoided anduniform action is assured. A further object is to provide 20 of the fuelpumps.

Another-object is to provide improved accessibility to various parts andaccessories of a barrel engine, and a further object is to provide animproved general arrangement for a barrel engine comprising a series ofunit sub-assemblies so constructed that they may be assembled in orderas follows: the engine mechanism proper including the pistons as anoperable mechanism; the cylinders in two groups, one at each end of theengine casing; a valve and accessory assembly at each-end; and theblower unit at one end and the power offtake gearing or coupling at theother.

Another object is to provide for axial fiow of the cooling medium thruthe jackets of the individual cylinder units to insure their uniformcooling and to insure especially the cooling of the port bridges. Thewabbler case is jacketed to assist in cooling the oil and to form awater manifold connecting the inner ends of all cylinder water jackets,while the valve housings, also water-jacketed to assist in cooling thevalve, form the water manifolds connecting the outer ends of thecylinder water jackets. Circulation of the cooling medium by pumps maybe from the 45 wabbler casing jackets outwardly thru the cylinderjackets to the valve housings, or vice versa,

as desired, suitable radiators being included in the circuit as usual.

These and other objects and features of the 50 invention will be moreapparent from the following description in connection with the drawings,

in which: Fig. 1 is a longitudinal sectional view of the rear portion ofthe engine, it being under-' stood that the'forwardend is similar andthe 55 various parts symmetrically arranged to those shown exceptingonly the blower unit which serves both rear and forward groups ofcylinders. As usual, in longitudinal sectional drawings of barrelengines, projections of some of the parts behind the plane of thedrawing are omitted to avoid unnecessary confusion. Fig. 2 is atransverse section on the line 'I'--T of Fig. 1, showing the cylinderintake port arrangement Figs. 3V and 3M are sectional views of the discvalve system, taken on the lines VV and M-M of Fig. 1'.

Fig. 4 is an enlarged view of a portion of Fig. 1 showing the particulartype of port sealing means used in connection with the disc valve. Fig.5

- is a development of a portion of one of the sealing 70 rings and itsspring ring.

Referring to the drawings, engine shaft is operable inball bearings llmounted in casing 12. Wabbler I315, mounted on bearings 14 on shaft ID,the axis of the wabbler and its bearings being 7 inclinedtornado; theshaft. Wabbler'arms l5 means for controlling the timing of the operationhave suitable operable connections with piston members l6 which arereciprocable in guide surfaces l8 in casing I2 while piston rings I1slide in cylinders 26.

Cylinders are individual units, each bolted to casing 12 by bolts 2| andhaving an annular water jacket 24 and integral combustion chamberopenwater'jacket to direct the air as it enters cylinder 20. Ports 22are piston-controlled and ports 23 are controlled by disc valve which isrotatable on eccentric 3| fixedon shaft 16. Disc valve 30 has peripheralgear 32 engaging internal gear 33 carried by valve casing. member 34which member also has ports 35 opposite to and larger than combustionchamber ports 23. Ports 35 discharge into manifold 36 which is fastenedto casing member 34. Ports 31 thru valve disc 30 successively connecteach of ports 23 with its corresponding port 35. Chambers 38 and 39within valve disc 30 may be filled with cooling liquid. Combustionchamber ports 23 are sealed relative to the face of valve 30 by rings29, identical in construction with ordinary piston rings, and urgedagainst the face of valve 30 by springs 38 augmented by the gaseouspressure being confined. Valve ports 31 when not in alignment with ports23 are kept closed relative to the interior of the valve house ing bysealing plate 21 which is resiliently held against the face of, valve 30by springs 26 seated in casing member 40.

Casing member 40 is part of the housing for valve 30 and is bolted tocylinders 26 by bolts 4|. Casing member 40 has concentric cylindricalwalls 42 and 43 engaging casing l2 and forming an annular chamber 44enclosing cylinders 26 and forming a common windchest to supply ports 225| enclosed in casing members 52 and 53, the

latter having formed therein the diffuser by which the kinetic energy ofthe air deliveredby the impeller is converted into pressure. Impeller 5|is fixed on shaft 54 having an integral drive pinion 55. Bearings 56 and51, mounted in casing member 52, are fixed on shaft 54 on either side ofpinion 55 and are thus favorably situated to maintain pinion 55 incorrect alignment without undue deflection under load, and concentricwith casing member 52. 4

Casing members 52 of the blower units 56 pilot into holes in the blowerdrive housing whose two members 60 and 62 carry bearings 63 and 64 onwhich blower drive gear 65 runs. Thus accurate meshing of pinions 55with gear 65 is assured. Drive housing member 66 is piloted onto bearing6| of shaft l0, locating the blower drive assembly concentric with shaftl0. Housing member 60 is fastened to valve casing member 34 by bolts 66.

Splines 61 fixed on shaft l6 engage internal splines on inner torquecushion member 68 which is surrounded by outer cushion member 69.Cushion members 68 and 69 have interlocking teeth between which springs16 are tangentially.

outwardly by light springs I? to engage their shoe portions with theinside of gear 85, forming a friction clutch by which gear 65 is driven.

Accessory drive gear 8!! is fixed on shaft I and engages a plurality ofaccessory driven gears 8! each of which is mounted in ball bearings 82and 83 secured to inner wall 42 of valve casing member Q0. Variousaccessories such as the oil pump 84 indicated in Fig. 1, are mounted onbosses formed on outer wall 13 of casing member 30. Each accessory hasits own drive shaft 85 extending between adjacent cylinders 29 thru asuitable oil-tight housing across windchest it and engaging a drivengear M with a splined connection 7 Fuel pump cam 90 is fixed on shaftl8. Surrounding fuel pump 90 is a cage member 95 fitted into inner walld2 of casing member 68 in a manner permitting angular adjustment of cagemember 9i by any convenient means. Cage member St has radial cylinders92 .one for each cylinder 26 of the group. In each cylinder 92,

cam follower 93 is reciprocable with its roller engaging cam 96. Eachcam follower 93 is provided with segmental shoe 9t Whose ends are a freefit in peripheral groove 95 in cage member di. Each shoe 93 engages apushrod 96 which extends radially outward thru a suitable oil-tighthousing across windchest at between adjacent cylinders 29, to operatefuel pump 9'0 which is associated with an injection nozzle 98 for eachcombustion chamber of the several cylinders 2d. Push rod spring as isprovided to return push rod 96 and cam follower 93.

Engine casing l 2 is provided with water jackets H) which assist'incooling the oil and also serve as a manifold communicating with theindividual water jackets 2 of cylinders 20. The valve housing is alsowater-jacketed and the casing member 18 serves as a manifold to connectthe outer ends of the individual water jackets 2d of cylinders 25 Thebridges 25 between intake ports 23 are also water-jacketed.

In assembling the mechanism, wabbler i3 is assembled on. bearings Hi onshaft id, and the shaft iii in bearings H in casing 52. Then pistonmembers i 6, followed by wabbler arms i5 and their operable connections,may be assembled 'thru handholes in casing l2. The engine mechanismproper is now assembled as an operable unit. Then cylinders 20 may bebolted to casing 52.

An accessory drive gear 8d and fuel pump cam 9b are assembled on eachend of shaft it. Driven gears 85 and their bearings 82 and 3, and thenpush rods 96, springs 99, and cage member 9! with cam followers 93, areassembled in casing member 43, two such assemblies being bolted tocylinders 20. Accessories with their drive shafts 85, and fuel pumps 9?and nozzles 98 may then be added.

Eccentrics 35 are added to shaft H3, with valves 35? on them, and thevalves are timed, and casings 3 t assembled and bolted to casings lii.Then bearing 65 and splined member 6? may be added to shaft If; anddrawn up with the lock nut.

The blower drive unit assembled in casing members so and 62 may then bepiloted onto bearing 6i, splines 6'7 mating with those of member 68, andthe unit bolted to casing 36. Blower units 58 may be assembled to casingmember 62 either before or after assembly of the'drive unit to casing34. To assemble a blower unit 5b in casing 62, insert thepinion-containing end of the unit and hook it over gear 85, then moveinwardly until casing 52 can pilot into the hole in casing 62, and pressthe pilot into place. Then bolt casing 53 to casing 62. With accuratemachining of the parts, pinions 55 will be precisely located and held inthe designed position relative to gear 65.

Manifold 36, in two parts, may then be assembled, and conduits 45connected, after which the various controls and the exterior oil, fuel,and cooling system plumbing may be attended to. Operation.-Rotation ofshaft l9 will be accompanied by reciprocation of. piston members l5 bythe operable action of the wabbler mechanism in a known manner, detailsof which are not included in the present invention. Rotation of sh ft l0will also drive blower units 59 in a manner hereinafter described, todeliver air thru conduits 65 to windchests id, and whenever the pistonsuncover ports 22, the air is directed into cylinders 2i! by ports 22 ina manner causing a high-speed swirling action. Somewhat before ports 22of a given cylinder are opened, its port 23 is opened by the motion ofvalve 30, permitting discharge of the exhaust thru ports 37 and 35 tomanifold lid, so that when ports 22 open, the swirling scavenge caneffectively clear the cylinder. Valve 36 is timed to close port 23somewhat before ports 22 are closed by the piston, permitting thecylinder to be supercharged approximately to blower pressure. Theoperation of valve 30 is described in greater detail hereinafter.

With cylinder 28 scavenged and charged with air, the piston nextcompresses the air, and when near top center, cam 90 operates one of theradiating members of the fuel system as hereinafter described, to causethe corresponding nozzle 98 to inject a shot of fuel into the combustionchamber. The piston is driven downward again by the ensuing combustionand expansion of the gases, to repeat the cycle.

Since both groups of cylinders are working cylinders operating on thetwo-stroke cycle, an outside source of air for combustion must beprovided. Splines it"! drive inner cushion member iiii'which drivesouter cushion member 69 thru springs 70, these members comprising aspring coupling. The action of springs 72 augmented by centrifugal forceacting on segmental shoe members H frictionally engages shoe members Wwith the interior of gear 65 to drive it, and drive gear 55 drivespinions 55 and impellers 5! at high speed.

Shock loading on the gear teeth'is avoided by the yielding nature oftorque cushion springs ill, by the yieldable overload slip ability ofclutch shoes 1i, and by the flywheel effect of gear 65 which resistssudden changes in velocity. However, even these comprehensive andeffective means of protecting the gear teeth would not save them if thegears were severely overloaded as they would be if a single blower wereused for so large an engine. Attempts to design a drive with reasonablegear tooth loads for such an engine have been unsatisfactory. A systemof s ev eral smaller blowers in accordance with the present inventionseems a much better way. Tooth loadings are reasonable, the symmetry ofthe drive system in helpful, and the method of mounting each gear on apair of adequate bearings accurately located and rigidly supported, alsocontributes to success. action, increasing the torque capacity about asthe square of the speed, is provided because it Centrifugal clutch v 50the piston is at 'top center la twice as fast, and big, as if the. valvesame speed,

' Just the same if the valve large diameter gears.

more nearly suits the requirements than any fixed capacity clutch can.

Any breathing system suitable for a two-stroke engine could be used inthe normal two-stroke round engine, but uniflow scavenge with portedintake and exhaust controlled by valves is preferred. Any suitable valvesystem could be used including poppet valves, but the disc valve systemillustrated has numerous advantages. As

shaft l0 rotates, valve 39 is carried around bodily on eccentric 3|while engagement of gears 32 and 33 rotates valve 39 on eccentric 3| ata speed slower than that of shaft l9 and in the opposite direction, ascan be understood from astudy of Fig. 3. The number and proportions ofports 31- in valve 30 are arranged to cooperate with the trochoidalmovement of the valve to produce the I desired port timing. The peculiaradvantages of (radial distance of port 23 from shaft 10) (radius of gear33) (number of cylinders in the group) -1 of port 23 when the piston isat bottom center is proportional to:

(radial distance of port 23 from shaft l0)+ (nsdius of gear 33) (numberof cylindersin the groupi 1 From the former ratio it is obvious that ifgear 33 had the same radius as the cylinder pitch of the first ratiowould be zero,

circle, the value the instantaneous axis of valve signifying that 40disc 30 would be the axis of port 23 when the piston is at top center".Practically speaking, the valve. would stop when the pressure is atpeak. a desirable condition from the standpoint of the sealing rings andtheir wear. This condition could be provided by constructing gear 33 ona separate disc axially spaced and beyond manifold 39 from the valveproper. with gear 33 larger than the pitch circle of ports 23 as shown,the velocity of valve 39 relative to port 23 when is still quite slow,but reversed in direction from that during most of the cycle. From thesecond ratio it is obvious that the larger gear 33 is made, the fasterthe ports in a two-stroke engine will open and close and the larger theports in the valve can be made.

i and 3 I With proportions such as those of Figs. the speed of the valvewhen the ports open and close, relative to the ports 23, is about fourtimes that when pressures are at peak. Port action the ports can betwice as were an ordinary rotary valve running concentric with the shaftat the (i. e. one-eighth shaft speed for nine cylinders with theproportions shown). The

breathing ability can thus be about four times more free.

Thus the applica ion of the eccentrically driven disc valve to thetwo-stroke engine gains new and important ends. and the advantages wouldhold were used for intake instead of for exhaust, or for both. Thepeculiar motion of the valve is in every way advantageous for two-strokecycle operation, and the advantages are greater by'the use of relativelyThe speed of the valve The speed of the valve face relative to thecenter relative to the port sealing means and the easing against whichthe valve is pressed by cylinder pressure, is relatively slow during thehigh pressure portions of ,the cycle, while the speed during portopening and closing is several times faster, providing quick portopening and closing and permitting very large ports.

The action of sealing rings 29 relative to their concentric grooves incasing member 40 and relative to the face of valve 90, is similar tothat of ordinary piston rings, except that initial contact of rings 29with valve 30 is insured by spring rings 28. (.ontact having been made,the pres-' sure trying to leak past rings 29 presses them outwardagainst the outer walls of their grooves, and gets under them to pressthem against the face of valve 39, precisely as the pressure gets behinda piston ring to press it against the cylinder wall and groove. Therotary and orbital movement of valve 39 induces rings 29 to rotateslowly in their grooves, preventing scoring, insuring even wear andperfect seal.

The masses of eccentrics 3| and valves 30 are designed of right amountso that the couple produced by their rotation with shaft ill will offsetthe couple arising from piston reciprocation, to produce practicallyperfect mechanical balance, in a known manner. In the fuel system, cam99 operates successively the cam followers 93,- and each drives itspushrod 96 outward to operate the corresponding pump 91, and a shot offuel is injected thereby into the appropriate combustion chamber thrunozzle 99. Spring 99 returns cam follower 93 and pushrod 99 after theinjection stroke. has its own return spring, as is known.

To adjust the timing of the fuel injection, cage member 9| is adjustedangularly by any suitable control means, shoes 9l stili riding on theirrespective push rods 96. When the axes of cam followers 93 aresomewhat'out of line with the axes of pushrods 99, the length of stroke of fuelpumps 91 is slightly shorter, but the discrepancy is very small and ofno significance in viewof the fact that the pump is so constructed thatonly a small central portion of its piston stroke is effective anyway. a

The various accessories are driven by gears and SI thru their severalradiating shafts 95. Of these accessories, the water pumps may circulatecooling fluid thru radiators of well-known types, pumping the fluid intojackets 89 in casing l2, from whence it flows axially outward thru theseveral jackets 24 of individual cylinder units 29 to jackets in casingmembers 49 and 34, when it may be returned to the pumps and radiators.Alternately, the flow could be reversed. One of the most constrictedparts of the circuit is where the water goes thru the intake portbridges; the velocity at these points will therefore be high, and thebridges eflectively cooled. All water system gaskets are clamped betweenplane surfaces so that leakage canbe prevented. The combustion chamberproper of each cylinder 20 is not directly water-jacketed; it isdesirable in a Diesel engine for the combustion chamber to run ratherhot. This condition could be avoided if the engine were to be run on theOtto cycle.

Other accessories may include the oil pumps, one of which is indicatedat 93. Oil is circulated thru shaft ID as an oil main, which can betapped wherever necessary. Oil is fed out thru eccentric II to flllchambers 38 and 39 in valve 39 by centrifugal action, to assist incooling the valve, the

Pump 91 7 tion as expressed in 2,222,294 a overflow from theinner lip ofchamber 39 being returned to the sump from which it can be sent thru oilcoolers by the scavenge pump in a known manner.

Having thus described the invention, its construction, assembly, andoperation, it is obvious that all the objects as stated herein have beenattained. The invention has been described as a normal round enginesubstantially complete with its various accessories as a uniquelycompact source of smooth and eihcient power. Certain features of theinvention are applicable to other types of engines and it' is understoodthat they may be so applied, construction and in the'arrangement of thevarious parts of the invention may be made, without departing from thespirit or scope of the inventhe following claims.

I claim:

l. A two-stroke normal barrel engine comprising a shaft, cylindersparallel to said shaft, piston members operable in said cylinders, awabbler mechanism operably connecting said piston members to the centralportion of. said shaft, a pair of eccentrics fixed on said shaft towardthe ends thereof, plate valves rotatable on said eccentrics, saideccentrics and valves being so constructed and arranged that thecentrifugal couple thereof during operation will be opposite to andsubstantially equal to the inertia couple produced by operation of saidpiston members with said wabbler mechanism, means fordriving and thatother changes in the plate valve members,

said valves comprising gears on said valves and gears fixed relative tosaid cylinders and meshing therewith, and means for providing uniflowscavenging thru said cylinders, said uniflow scavenging means comprisinginlet ports tangentially inclined in the walls of said cylinders andcontrolled by said pistons, and exhaust ports in the heads of saidcylinders and controlled by said plate valves.

2. A two-stroke engine comprising a shaft, cylinders parallel to saidshaft, piston members operable in said cylinders, a wabbler mechanismoperably connecting said piston members to the central portion of saidshaft, ports in the heads of said cylinders and spaced about said shaftin a plane normal thereto, a pair of plate valve members controllingsaid ports, ports thru said and means for driving said valves uniformlyand at constant rate relative to said shaft so as to cause said valveports to register successively with said cylinder ports and in such amanner that the speed of said valve relative to said cylinder ports willbe relatively slow when the pressures in said cylinders are high, andseveral times faster whenever said valve ports are registering with saidcylinder -ports, said valves and their drive means being'so constructedand arrangedas to produce a centrifugal couple during operation opposedto the couple resulting from the inertia of said piston members.

S. HALL.

